Training in Research on Addictions in Interdisciplinary NeuroAIDS (TRAIN) Interdisciplinary clinical research on the combined effects of substance abuse and HIV infection on brain structure and function is of considerable relevance to public health initiatives. However, there are presently very few laboratories conducting such research and no current training programs dedicated to preparing the next generation of investigators in clinical research at the intersection of addictions and neuroAIDS. Accordingly, we propose to establish a new Ruth L. Kirschstein National Research Service Award Institutional Training Grant (NRSA T32) entitled, Training in Research on Addictions in Interdisciplinary NeuroAIDS (TRAIN). The aim of TRAIN is to prepare a steady state of four pre-doctoral students and two post-doctoral fellows in clinical neuropsychology for multidisciplinary academic careers focused on the central nervous system (CNS) effects of substance abuse and HIV infection. We will recruit a highly qualified and culturally diverse cohort of trainees that demonstrate promise toward achieving productive academic careers. The TRAIN program will emphasize research training in three primary, interrelated CNS outcomes, which were selected because of their salience and